Technical Abstract:
Lesquerella (Lesquerella fendleri) and guayule (Parthenium argentatum) are potential alternative crops that are being studied for commercial production. Understanding the minimum temperatures for seed germination and seedling growth are important in determining the potential areas for seed production of these crops. This information is useful in estimating growing degree days required for plant production. Climatic data can then be used to determine the potential area for production.
The objectives of this study were to determine the minimum temperature of germination and seedling growth, and to screen ecotypes for germination and growth characteristics. We will then conduct field studies at various elevations to assess temperature differences in the field, and to see how the field data compare with laboratory results.
A temperature gradient table was constructed to allow germination of ecotypes over a range of temperatures in the laboratory. A 2.54 cm-thick aluminum block 0.61 m wide and 1.22 m long was insulated on all sides with Styrofoam board insulation. Water baths were connected to each end of the aluminum block and used to control the temperature gradient. Seeds were germinated in Petri dishes placed on the table and time to germination was observed. Time to 5 mm root length and time to 5 mm shoot length were also measured to assess the minimum temperature for seedling survival and growth.
Preliminary laboratory data have shown varietal differences in time to germination, as well as in seedling growth characteristics. Further investigation is being carried out to assess adequately the temperature effects on germination and growth variables.